The invention relates generally to welding systems and, more particularly, to wire feed assemblies of such systems.
A common metal welding technique employs the heat generated by electrical arcing to transition a portion of a workpiece to a molten state, and the addition of filler metal from a wire or electrode. One technique that employs this arcing principle is wire-feed welding. At its essence, wire-feed welding involves routing welding current from a power source into an electrode that is brought into close proximity or contact with the workpiece. When the electrode is sufficiently close to or touching the workpiece, current arcs from the electrode to the workpiece, completing a circuit and generating sufficient heat to melt and weld the workpiece. Often, the electrode is consumed and becomes part of the weld itself. Thus, new wire electrode is advanced, continuously replacing the consumed electrode and maintaining the welding arc. If the welding device is properly adjusted, the wire-feed advancement and arcing cycle progresses smoothly, providing a good weld. One common type of wire-feed welding is metal inert gas or “MIG” welding.
In typical wire-feed systems, wire electrode is advanced by a wire feeder and directed through a welding cable, into a torch assembly, and into a contact tip housed within the torch assembly. Electrical current is routed from the welding cable to the wire electrode through the contact tip. When a trigger on the welding torch is operated, wire electrode is advanced toward the contact tip, at which point current is conducted from the contact tip into the advancing electrode.
As will be appreciated, it may be desirable to change the type of wire electrode used by a welding system based on the particular workpiece. For instance, welding operations performed on two different workpieces may benefit from using wire electrodes of different sizes or compositions. However, wire feeders within such systems typically include drive rolls disposed at fixed positions with respect to a path in which a wire electrode is advanced. These typical drive rolls may have a single groove configured to receive a particular type of wire or a pair of grooves on opposite ends of the drive roll for receiving two types of wire. In the case of the former, an operator is generally required to remove the drive roll from the system and replace it with a different drive roll in order to configure the system for use with a different wire type. In the latter instance, the two-groove drive roll must be removed from the system, reversed, and reinstalled to align the desired groove with the wire path. Consequently, these common drive rolls are generally configured to advance only one or two types of wire electrodes, and typically require disassembly of a portion of the welding system in order to change between various wire types.
Therefore, there exists a need for an improved drive assembly for welding devices that facilitates quicker and easier configuration of the welding system for use with different wire electrodes.